Change cusolver back to default stream
Change cusolver back to default stream

* Synchronize the ArrayFire stream when cusolver getHandle is done
* The stream form of cusolver require using cudaDeviceSynchronize and
cudaStreamSynchronize all over the place
* Even then, getrs in solve_lu failed on any stream other than 0
* patch available at: https://gist.github.com/shehzan10/414c3d04a40e7c4a03ed3c2e1b9072e7

merlin-ext/arrayfire,victorv/arrayfire,ghisvail/arrayfire,munnybearz/arrayfire,shehzan10/arrayfire,victorv/arrayfire,merlin-ext/arrayfire,9prady9/arrayfire,victorv/arrayfire,ghisvail/arrayfire,arrayfire/arrayfire,munnybearz/arrayfire,ghisvail/arrayfire,ghisvail/arrayfire,marbre/arrayfire,shehzan10/arrayfire,umar456/arrayfire,9prady9/arrayfire,umar456/arrayfire,marbre/arrayfire,marbre/arrayfire,victorv/arrayfire,9prady9/arrayfire,shehzan10/arrayfire,merlin-ext/arrayfire,arrayfire/arrayfire,umar456/arrayfire,marbre/arrayfire,arrayfire/arrayfire,merlin-ext/arrayfire,umar456/arrayfire,9prady9/arrayfire,munnybearz/arrayfire,arrayfire/arrayfire,shehzan10/arrayfire